The present invention relates to a friction damper which has been specifically designed for washing machines and the like.
As is known, the basket of a washing machine is affected, during the rotary movement thereof, by oscillations due to a dynamic unbalancing of the rotary mass of the basket and of the lineN held therein.
Said basket is usually suspended, by springs, to the washing machine frame and, in order to dampen the above mentioned oscillations or vibrations, two dampers or shock absorbers are conventionally used, each of which is coupled, at the bottom end portion thereof, to the washing machine frame and, at the top portion thereof, to the basket.
Dampers for a washing machine application comprise friction dampers, which are substantially constituted of a shell, having a substantially cylindrical shape, inside of which a rod is adapted to slide, between the rod and shell being arranged a gasket made of a friction material, said gasket being rigidly coupled to the shell or to the rod.
This gasket is designed for providing a friction braking operation in order to brake the mutual displacement of the rod with respect to the shell.
While the above mentioned dampers have been found to provide an efficient damping of the basket oscillations in washing machines, they, however, generate a comparatively high friction rubbing during the washing machine washing steps thereby causing the basket to oscillate, even if in a comparatively small degree. Consequently, the dampers are quickly worn out, in particular at the region thereof which is engaged with the friction material gasket, thereby quickly reducing the operating efficiency of this gasket which must be frequently replaced.